Consuming chlorella as a supplement improved levels of total cholesterol, systolic blood pressure, and other indicators of cardiovascular disease risk—but may be a better value to unhealthy populations, according to a new meta-analysis.

Performed by researchers from Shahrekord University in Iran, the meta-analysis looked at relevant studies up to January 2017.

“The effect of Chlorella supplementation on cardiovascular risk factors is considered in some human randomized clinical trials; however, the results are not fully conclusive,”​ according to their report, published​​ in the journal Clinical Nutrition​.

Differences in results may have come from the variety of study designs and characteristics of study participants, hence, the researchers of this present study wanted to shed more light on what scientific literature on chlorella says so far about its health benefits.

Inclusion criteria​

The researchers looked at studies that were randomized controlled trials, where chlorella supplementation was compared to a control.

They also focused on studies that had adequate data on changes of lipid profile, blood pressure, BMI, and fasting blood glucose—typical indicators of cardiovascular disease risk.

In sum, they aggregated 19 studies in the meta-analysis, with a total of 797 study participants from Japan (which made up the bulk of the studies), Korea, and Iran.

The health condition of study participants included in the analysis varied, with a range of healthy, borderline hypertensive, mild hypertensive, hypercholesterolemic, smoking, and pregnant subjects.

‘Chlorella significantly reduced total cholesterol’​

Data from all the studies combined revealed a link between chlorella consumption and the lowering of total cholesterol, which the researchers argue is because of the bioactive compounds in the single-celled microalgae that can optimize metabolism of lipids.

“The water-soluble fibers, which are high in Chlorella (13 g/100 g), bind to the digested fat and reduce the absorption of sterols (such as cholesterol) from the intestine; therefore, the amount of sterols in the feces increase,”​ they argued.

From their analysis, they also found that intake of chlorella was “more effective in unhealthy subjects compared to healthy ones,” ​as it significantly improved indicators such as blood pressure and total cholesterol.

However, the researchers wrote that effects on body mass index (BMI) was not conclusive. “Further studies on the effect of Chlorella in combination with various natural antioxidants, lipid-lowering agents, or glucose-lowering drugs should be carried out to assess the efficacy of combination therapy on cardio-metabolic health.”​